"Telescope guide" for beginners to those who are suffering "What kind of telescope is good for starting astronomical observation?"
If you are obsessed with the charm of the star world that colors the night sky, you will want to get the first astronomical telescope as soon as possible and you will want to point to the stars, but many items are lining up on shops and the net Often he / she often wonders whether to buy one. Ed Ting, who has been reviewing numerous astronomical telescopes, has published advice for beginners on how to select the astronomical telescope by any idea.
Advice for New Astronomers
Ed Ting is on his own siteA review of over 100 astronomical telescopesIt is the person who is doing, and it describes the knowledge when choosing "the first one" based on that experience.
◆ Before you buy an astronomical telescope
As a beginner starts astronomical observation, Ting suddenly goes not to buy an astronomical telescope, but first about starsTo add knowledge,Sky & amp; TelescopeYaAstronomylikeSubscribing to special journals and reading, And actually do observationI join astronomy club etc.It is important to know what kind of equipment various people are using to observe. Because Ting is living abroad, recommended journals are local, but in JapanAstronomical guideYaStar naviMay be a monthly magazine such as.
And then, although it is felt surprising, Ting recommends that you obtain "binoculars" if possible before the astronomical telescope. Even if there is no astronomical telescope at home, people who have binoculars of any kind should be quite good, and even people who actually use astronomical telescope also use binoculars in common. The size of the binoculars should be at least 7 x 35, preferably around 7 x 50. Actually, amongst celestial fans, there are many cases that models of about 10 × 50 are used.
◆ And how to choose an astronomical telescope
Once you have acquired some knowledge and experience, I will consider introducing the astronomical telescope soon. In that case it is often written in the explanation of the telescope for beginners that you have to be careful as a mistake that is likely to fall into thatDo not get caught by magnification displayTing emphasizes. The reason is,The role of the astronomical telescope is not to enlarge the image, but to capture more lightIn order to realize thisIt is best to choose a telescope with as large a diameter as possibleAnd that. If you mistakenly mistakenly chose it by advertisement complaints such as "magnificent magnification × ×!", When you actually saw a star, you could only see a binary and a dark image because the light intensity was insufficient It is said that attention is necessary because it falls into the situation that.
In choosing a telescope, it is necessary to know that there are roughly three types of astronomical telescope entering as a beginner's choice.
Part 1:Refractive telescope(Refraction formula)
Refraction telescope is a type of telescope having a shape of an elongated cylinder, and many people think of this kind first when asking "astronomical telescope". A refractoring telescope is a telescope that enlarges an image by combining multiple optical lenses on a straight line, and it is also for beginners that little adjustment is required.
However, since the light coming from the star passes through multiple lenses, in principlechromatic aberrationIt is inevitable to occur, and there is a disadvantage that color misregistration occurs.
Part 2:Newtonian telescope(Reflection type)
The "Newtonian telescope" listed secondly has a structure that reflects light by a concave mirror to form an image, so it is a major feature that it has the merit that chromatic aberration does not occur in principle. As its name suggests, it is also known as a telescope devised by physicist Isaac Newton.
One of the merit is that the Newtonian telescope can be created at a relatively low cost. However, since it is necessary to arrange a secondary mirror in the lens barrel, it is disadvantage that some influence on the contrast of the image can not be avoided. Also, it seems to be said that there is a need for doing adjustment of the optical system frequently, for beginners a little hurd is high.
Part 3:Schmidt Cassegrain type telescope(Catadioptric type)
The Schmidt Cassegrain telescope sometimes called "shimikase", and that group can be saidMakuofuf Cassegrain formulaYaSchmidt Newton formulaThe third option is the telescope. This is a type of telescope having both the refraction formula and the reflection type as described above, and it is one of the merits that it is easy to miniaturize.
This telescope has a system of reflecting light with a main mirror of a concave mirror at the bottom of a lens barrel like a Newton type (reflection type), and reflecting it again with a double mirror in the whole lens barrel to observe it.
The excellent part of Shimakase is that it is easy to miniaturize due to the structure that reflects light, that it can be made cheaper than a refractor, and a wide variety of after parts are enriched, so even observation in cooperation with a computer It is easy to handle. The disadvantage is that there is a potential existence of the possibility that the image quality will drop for the other two types due to structural reasons.
◆ Which one should you choose for these three
Then, which one of these three types of telescope should be chosen actually? Ting first answers "it depends on the person himself or the purpose." Each telescope has advantages and disadvantages, and it is also an important factor to consider the budget. Ting also said that he also had the itinerant that he changed from refractoring through Newton's formula to shimakasa and he used a lot of famous manufacturers such as Criterion, Meade and Celestron.
An important point that Ting says is as follows.
· Many people choose Shimikase as the first one even though there is a refraction formula that is optically superior and a reflection type that is cheaper in price. The reason for this is probably because it can be obtained relatively cheaply even with a large diameter type of 8 inches (about 20 cm), for example, it is easy to handle. Even if it is the same 8 inches, it is a reflector type, moreoverEquatorial ceremonial standIt becomes difficult to handle if it is on the one mentioned above, and huge space becomes necessary so that it is better to build another building for observation after reaching refraction formula.
· Reflecting telescope of 4.5 inches to 6 inches is recommended for beginners. A certain level of image quality can be secured with expense of several ten thousand yen level, handling and carrying are convenient.
· Products sold for introductory use, refractory type and selling magnification should be avoided. Especially the type of "60 mm at 675 times" can not be used. In general, 50 to 60 times per inch is said to be a line guaranteed quality, so if it is 60 mm type it can be said that 120 to 144 times is reasonable magnification. Anyway when you buy a telescope do not get caught by the magnification, and be careful about what is sold cheaply at department stores, home centers, online mail order.
· The excellent point of the reflecting telescope is that it is easiest to observe in these three types. From this point of view, the refraction formula where the eyepiece is at the bottom of the lens barrel, in some cases, has difficulty in observation.
· Although it may be out of the spirit, the astronomical observer gradually realizes that it is impossible to narrow down one "one that is best for you", and puts out hands on the second and third telescope . But if I put this in one corner of my head, "I bought an 80 mm refraction formula and after a few years I got a 10 inch diameter (about 25 cm)Dobsonian telescopeYou can assemble a way of thinking that you get the balance by getting the balance.
·Taking astronomical pictures is not to be taken into consideration for the time being. Because more know-how and equipment are needed to take pictures. Some people quit celestial fans because of that.
·Equipment otakuIt is better that you do not fall into. People who are looking at the catalog for many hours a day already have that tendency. First of all get one. Then you will feel better.
So ◆, what should I get after all?
Ting Mr. Ting will come back to here again once we have put together the conceptual theory. Based on many experiences, Ting recommended one for beginners is a reflection telescope with a caliber of 8 inches (about 20 cm), and was placed on the Dobsonian standOrion SkyQuest XT 8It is said to be a model called.
This model is characterized by having a light quantity with a large diameter lens barrel, characterized by having a large caliber telescope on a Dobsonian stand which a beginner can handle easily, and it is also relatively inexpensive. The price of the net shop at the time of article creation is 389.99 dollars (about 43,000 yen). However, it is important to note that the length of the lens barrel is about 1 meter and the weight is about 19 kg in full set. Some enthusiasts buy wheels with locking mechanisms at home centers, and some people remodel mobile by DIY.
Orion SkyQuest XT8 Classic Dobsonian Telescope | Orion Telescopes
This "ease of carrying" is actually a very important point, and if you lose the trouble of setup even more than the precautionary observation date, you will lose the meaning of buying a telescope. It is also important to devise measures such as installing moving wheels as described above, and to take measures that do not bother with annoying preparations.
Also, what type of eyepiece (eyepiece) will be chosen becomes important, but according to Ting, initially it can be easily expanded to three or four eyepieces by size, "Barrow Lens", and It is recommended that you prepare several filters if possible. Anyway, since the eyepiece is a place where it is easy for maniacs to become a beginner and a veteran, it seems to be better if you do not think too much until you get used to it.
◆ What kind of sight can actually be seen?
It is a big point to worry about how you can really see stars with the astronomical telescope you got in this way. Everyone imagines the magnificent celestial bodies and inflates expectations, but Ting says that it is important to have 'realistic expectations' there. For example, many beginners expect Saturn's appearance that the ring looks clearly as follows ... ...
In fact it can be seen in many cases the appearance of Saturn like this. It seems to simulate the image captured by a telescope with a caliber of 6 inches and a magnification of 100 times.
Andromeda galaxy shot by professional is like this ... ...
When it is the environment of an amateur astronomer, the actual appearance is like this.
Globular clusters in Hercules'M13It will look something like this when the professional photographs ......
This is about a beginner level. Of course, by enriching the equipment you will be able to get a sight close to a professional, but it goes without saying that a lot of experience and expense are required to get there.
Ting finally summarizes advice for beginners to choose the first astronomical telescope as follows.
1: Binoculars can be a substitute for telescope, even for cheap ones, and even a good companion for telescope observation.
2: Avoid searching for telescopes at department stores, toy stores, non-professional shops dealing with science goods. Anyways,Do not buy cheap goods that are sold at department stores and home centers absolutely.
3: The most important task of the telescope is to collect light. Therefore, the same thing can always be said, but beginners should choose the type of large caliber as much as possible. The Dobsonian Reflecting Telescope with a caliber of 6 inches is perfect for beginners.
4: However, if the equipment is too large, it will gradually become unused. Please think about handling, do not forget realistic eyes.
5: Eyepieces are not necessary for the time being except for the first three to four chosen carefully. At the very least you should choose the Körner formula and its derivation method. In order to raise the magnification quickly, it is one of means to use the barro lens.
6: If you absolutely want to mention one, we recommend a Dobsonian reflection telescope with a caliber of 6 or 8 inches
7: If you are going to observe the land during the day, not a telescopeSpotting scopeIt is better to use (or field scope).
8: Do not think about astronomical photographs.
In this way, Ting sent advice based on abundant experience towards beginners. Ting'sReview pageIn addition to the enormous amount of telescope reviews are posted, astronomical photographs that were actually taken are also posted, especially Astronomy fans are worth seeing.